Three possible isomers of N-fused tetraphenylporphyrin ruthenium complexes, Ru(NFTPp)Cl(CO)(2) (2a-c), were isolated and fully characterized by NMR, IR, CV, UV-vis-NIR absorption, and X-ray crystallographic analyses. Each isomer was stable at ambient conditions and isomerization among 2a-c occurred at elevated temperature both in solution and in a solid state, through the intramolecular rotational pathways. Electronic structures of 2a-c were analyzed in detail by DFT study to reveal appreciable differences in the interaction between the NFTPp ligand and the Ru-Cl moiety.